离子液体中β-葡萄糖苷酶生物催化合成红景天甙

Biocatalytic Synthesis of Salidroside by β-Glucosidase in Ionic Liquids

比较了聚乙二醇修饰的β-葡萄糖苷酶在三种离子液体([bmim]PF6,[bmim]BF4,[bmim]Tf2N)及两种常用有机溶剂(1,4-二氧六环、正己烷)中的催化性能,确定了适宜的反应介质;考察了底物浓度、温度、体系含水量和反应时间等因素对β-葡萄糖苷酶催化合成红景天甙反应的影响.结果表明,在最佳反应介质[bmim]PF6存在下,底物酪醇浓度为70mmol/L,体系含水量2%,于50oC,反应24h时,高达88.5%的酪醇转化为红景天甙(即61.93mmo1/L).与有机溶剂相比,以[bmim]PF6为反应介质对酶促合成红景天甙的反应过程具有明显的强化作用.

β-Glucosidase modified with polyethylene glycol （PEG） was used as catalyst for the synthesis of salidroside from tyrosol and D-glucose,and its catalytic activity in three ionic liquids,[bmim]PF6,[bmim]BF4,and [bmim]Tf2N,and two common organic solvents,1,4-dioxane and n-hexane,was measured.Ionic liquid [bmim]PF6 was the optimal reaction medium,and different reaction conditions were optimized in it.A yield of 88.5% （product content of 61.93 mmo1/L） was obtained under the conditions of H2O content of 2%,temperature of 50 oC,tyrosol content of 70 mmo1/L,D-glucose/tyrosol molar ratio of 2,and reaction time of 24 h.The results suggest that both the modification with PEG and using ionic liquid [bmim]PF6 as reaction medium have obvious promoting effects on the enzymatic synthesis of salidroside.